Allow disabeling the language server for some file patterns

[luisdavim]

There are some issues when using this plugin with helm charts, now there's https://github.com/mrjosh/helm-ls and I'd like to use that when editing files from a helm chart instead of the yaml-language-server, in my coc-settings.json I have the following:

{
  "languageserver": {
    "helm-ls": {
      "command": "helm-ls",
      "args": ["serve"],
      "filetypes": ["helm", "helmfile"],
      "rootPatterns": ["Chart.yaml"]
    }
  },
  "yaml.format.bracketSpacing": false,
  "yaml.schemaStore.enable": true,
  "yaml.hover": true,
  "yaml.completion": true,
  "yaml.validate": true,
  //  "yaml.schemas": {
  //    "https://gist.githubusercontent.com/simnalamburt/2c3263b783ed3f4471bda9ca901bb69f/raw/9c2cd17d6f4683cf80b6360a2d53b33fd49556d7/allow-all-json-schema.json": "*template*/**/*"
  //  },
}

but I still get diagnostic errors from the yaml language server.